Automatically controlled system for ash disposal



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WlLL-AM D-HOGH S BY ATTORNEY April 12, 1955 w. D. HUGHES 2,706,136

AUTOMATICALLY CONTROLLED SYSTEM FOR ASH DISPOSAL Filed June 21, 1950 5Sheets-Sheet 4 a6 A-c men um g tgtg aunnv Pecos: in-re mmcmnn COT-OFFMil CUT'OW 1'23 CUT-(FF 5mg CUT-OFF M52 (LIT-OFF GQTQ S INVENTOR.WILL-(AM D. HUQH Ba /K ATTORNEY April 12, 1955 w. D. HUGHES 2,706,136

AUTOMATICALLY CONTROLLED SYSTEM FOR ASH DISPOSAL Filed June 21, 1950 5Sheets-Sheet 5 sauezron. "iieififiif w 05 65 Q-CR L I GR AUTO BOI LERAu'ro some:

Auro BOILER INVENTOR. NH-LIAM D- HusHEs BY g HTTORNEV United StatesPatent AUTOMATICALLY CONTROLLED SYSTEM FOR ASH DISPOSAL William D.Hughes, Haddon Heights, N. J., assignor to Beaumont Birch Company,Philadelphia, Pa., a corporation of Pennsylvania plants and other largeboiler installations, where the problem of ash removal and disposal inlarge quantities, continuously from a plurality of ash producing units,1s an important one.

In power plants of the coal burning type, and likewise in heating plantswhich utilize coal or other combustible material as fuel, the productionof ash from the various units is substantially continuous and varies inquantity depending upon the load imposed upon the power or heatingplant, as the case may be.

In such plants, it is customary to have a plurality of boiler or otherash producing units, which may be operated or shut down in varyingnumbers, as required to meet the varying load conditions. By utilizing anumber of smaller units, rather than one large unit, greater flexibilitymay be obtained in carrying the load most economically. However, with anincreasing number of boiler or other combustion and ash producing units,the problem of ash removal becomes greater in proportion. The greaterthe number of units, the greater the problem, both as to quantity of ashremoved and attendance required to effect removal of the ash in such amanner as not to interfere with proper combustion.

With modern power plants, and to a certain extent with heating plants,automatic operation is desirable for the reason'that varying loadconditions may be me! best by means responsive to variations in loadconditions, and also for economy in operation and certainty of controlbeyond anything possible with direct control by operators. Likewise, itis desirable to provide ash handling equipment for removing the ashaccumulation substantially continuously and in accordance with theproduction of the ash, which in turn, as hereinbefore indicated, dependsupon the varying load conditions imposed upon the plant.

It is, therefore, a primary object of this invention to provide animproved ash handling system for power plants and the like, which isadapted for operation with one or a plurality of ash producing unitssuch as boilers, and which is also adapted to be operated eitherautomatically or manually, as desired, by electrical control means.

It is a further object of this invention to provide an improved ashhandling system for a plurality of boiler or other ash producingcombustion units, which may selectively operate to withdraw ashesautomatically from each unit under electrical control, through themedium of timing relays and simplified circuit means interconnectingsuch relays, together with an improved ash handling apparatus adaptedfor remote control electrical operation.

A further and important object of the invention is to provide an ashhandling system for boiler plants and the like which provides for theremoval of ash progressively from each unit of the boiler plant througha simplified conduit system provided with vacuum jet control and rotaryfeeder means wholly electrical-relay controlled from a centralizedlocation.

It is desirable, in large boiler plant installations, to provide for thecontrol of all units from a centralized location, such as a panelconveniently located within the plant, not only to indicate thecondition of operation of the system, but also to provide a record ofany irregularity in the operation. A system embodying the presentinvention is particularly adapted for this atrangement, in that theelectronic control circuits are arranged for centralized switching andindicating control. Furthermore, in accordance with the invention, aplurality of control and timing relays are so interconnected with theapparatus to be controlled that both sequential operation of the variousash handling elements for each boiler unit, and manual operationthereof, may be provided through a minimum of switches and other controlelements adapted for panel board mounting.

It is, therefore, a still further object of this invention to provide anash handling system which is adapted for sequential control of aplurality of ash producing units, such as coal burning boilers or thelike, through the medium of a minimum number of electrical control andtimgig relays, wholly automatically or manually, as desire It is afurther and important object of the invention to provide an improved ashhandling system providing sequential control of a plurality of ashproducing units, which operates to remove ashes and other solidcombustion products wholly through conduit means under vacuum, withimproved feeder means therefor at each unit wholly under control thevacuum through electrical relay-controlled gates and electric motordrive means.

A closed conduit system for ash removal with vacuum involves the problemof maintaining the vacuum in the system while feeding materialtherethrough, and the sequential control of a system involving aplurality of feeding units for each boiler. The system of the presentinvention involves improved and simplified means for effectingsequential control in dependence upon the vacuum in the ash removalconduit system.

In one form of the invention, the vacuum is created in the conduitsystem by a steam jet under electrical control, and the electricalsystem is furthermore controlled by a vacuum switch also connected withthe vacuum system, together with rotary electric motor driven feedergates which serve to maintain the conduit closed while at the same timefeeding the ash directly into the conduit from each boiler or other ashproducing unit. Between the vacuum switch and the rotary feeder gates isa simplified electrical control system embodying a minimum number ofelectrical control and timing relays, together with electrical circuitsproviding for both individual and joint control of all boiler units bothautomatically and manually, as well as indicating and recording elementsas required for continuous operation of the plant.

It is, therefore, a further object of the invention to provide animproved sequential control system for multiple-unit ash handling andthe like, which operates to control the ash removal not only from oneunit in predetermined sequence from various points, but sequentiallyfrom unit to unit, wholly automatically, with a minimum of simplifiedand reliable operational and control elements, and which at the sametime is adapted for manual operation as desired, selectively or in anysequence.

The invention will further be understood from the following descriptionwhen considered in connection with the accompanying drawings, in which apresent preferred ash handling system and sequential control thereforare shown for a multiple unit boiler plant of the type used for steamdriven power plants and the like, and its scope is defined by theappended claims.

In the drawings:

Figure l is a schematic diagram showing an ash handling conduit systemand feeder and control means connected therewith, in accordance with theinvention;

Figure 2 is a front view of an electrical control panel or unit foroperation of the ash handling system shown in Figure 1, also arranged inaccordance with the invention;

Figures 3A and 3B, taken together, is a schematic circuit diagram of anash handling system provided with sequential and manual control, also inaccordance with the invention;

Figure 4 is a graph showing certain features of the operation of thesystem shown in Figures 3A and 3B; and

Figure 5 is a simplified schematic circuit diagram of the electricalsystem shown in Figures 3A and 3B, further illustrating the invention.

Referring to Figure 1, a branched, closed conduit system is shown forash removal from two boiler units of a power plant. Three main branches6, 7 and 8 are included in the present system. The branches 7 and 8serve boilers 10 and 9, respectively, indicated generally by the centerlines shown in the figure with respect to the diagrammaticrepresentation of the boiler room floor level. Each of the branches 7and 8 is supplied with ash through rotary feeder gates. Conduit 8, forboiler 9, is provided with four rotary feeder gates 11, 12, 13 and 14,while the branched conduit 7, for boiler 10, is provided with rotaryfeeder gates 15, 16, 17 and 18. In accordance with the invention, therotary feeder gates are operated in the same sequence as their numbereddesignations for clearing the boilers of ash from a plurality of pointson each boiler.

It will be noted that the branched conduit 8 is provided with a cut-01fgate 1, whereas the conduit 7 is provided with a cut-oif gate 2, botharranged to be electrically operated. In addition, conduit 6 is providedwith a similar cut-off gate 3. Stack hoppers 20 and 21 are connectedwith the conduit branches 7 and 8, respectively, through cut-off gates 5and 4, which are similar to the other cutoff gates and are arranged tobe electrically operated remotely.

The rotary feeder gates are each provided with a hopper 22, throughwhich the ashes pass from the boiler into the ash handling conduit andare driven by electric motors, rotary gates 11-14 being driven by motors25-28, while rotary gates 18 are driven by motors 30-33, all throughsuitable belt drives as indicated. While any suitable rotary gate feedermay be used, it may be considered that each rotary gate is of therotary-vane type for carrying the ash from the hoppers into the conduitwhen operated by the motor means. Each motor is provided with a controlunit connected therewith, as indicated at 35, and arranged to beconnected electrically with the remainder of the system, as will behereinafter described.

The cut-off gates 15 are likewise arranged to be electrically operatedthrough solenoid control elements 4044, also arranged to be connectedelectrically with the remainder of the system.

It will be noted that the ash conveying conduit branches 6, 7 and 8 arejoined with a common conduit 45, in which is located a steam jet 46directed to produce a vacuum on the system when supplied with steam.This conduit is connected with a relatively large ash receiver andseparator unit 47, into which it discharges the ashes and other productsof combustion drawn from the three branches 6, 7 and 8. Such ashreceiving separators are old and well known, and further description isbelieved to be unnecessary, except to point out that the ash-free air isdischarged through the open top outlet conduit 48, while the ashes areremoved from a suitable ash hopper indicated at 49 at the bottom of theseparator unit. The handling of the ashes beyond this point does notconcern the invention, although it may be pointed out that the usualconveyor belt system may be used.

The steam jet 46 is sup lied with operating steam from a supply pipe 50,with which it is connected to the boiler or other supply source (notshown), and the su ly of steam to the jet is controlled by a steam valve51 having an electrical solenoid control un t 52 connected herewith andadapted f r remote electrical control, as will hereinafter he described.

Also connected with the conduit section 45, common to all of the threebranches 6, 7 and 8, is a vacuum line 55 connected with a vacuum switch56 which is responsive to the vacuum conditions in the cond it foroperating a switch comprising a movable contact 57 and fixed contacts 58and 59. which m v be connected to the svstem for control pur oses. aswill be hereinafter described. As indicated in the drawing, the vacuumswitch contacts 57 and 58 are closed when the vacuum in the vacuum line55 and in the conduit svstem is substantially zero or at a minimum. Thiscondition obtains when the ash from the rotary feeder gates falls tosubstantially zero and the vacuum system draws air only through theconduit branches.

A vacuum gauge 60 may also be connected with the vacuum line throughsuitable piping 61, for reading the vacuum condition in the ashconveying conduit system. Likewise, a steam pressure gauge 63 isconnected through a steam pressure line 64 with the steam pressuresupply pipe 50 on the supply side of the valve 51, as indicated, tooperate when the steam is on, in operation. When the pressure is ofsufiicient value for proper operation, the steam gauge is arranged tooperate a control switch 65 which is connected into the system forcontrol purposes as will hereinafter appear.

The conduit branch 6, controlled by cut-off gate 3, serves to conveyashes from the rear pass portion of both boilers, and is provided withsuitable branches 67, 68 and 69, controlled by manual gates 70 throughwhich the various branches may be selected in clearing the rear passlines of ashes, as well as the bottom hopper of the boiler system.

The branch 6 and its connecting lines represent any additional ashremoval conduit connections which may be provided for the system to bemanually controlled at any time as desired, although, as willhereinafter appear, such branch conduit may be controlled automatically,if desired, as may the other branches. Accordingly, further descriptionis believed to be unnecessary, except to point out that the branch lines6769 are provided with suitable ash hoppers 71 through which ashes arecollected for application to the branch lines, and thence through branch6 to the ash receiver and separator 47 during certain portions of theoperation of the plant. Normally, however, the cut-off gate 3 is closed,cutting off all three branches, except when required to clear the rearpass and bottom hopper lines.

Referring now to Figure 2, in which like parts are designated by thesame reference characters as in Figure 1, a control unit for the systemmay be provided, and arranged with a control panel 75 on the frontthereof, which is adapted to contain the control and indicating elementsof the system, whereby electrical remote control is provided. Thecontrol unit, furthermore, serves to house all of the electrical relaysand other apparatus conveniently and effectively, while the front of thepanel contains a grouping of instruments and controls adapted tofacilitate operation of the system by an attendant.

In the present example, the control unit panel is provided with thesteam pressure gauge 63 and the vacuum gauge 60 in the upper portion ofthe panel on opposite sides of an operating chart indicated at 76. Aseries of indicating lamps, and push button control elements form thenext lowermost line of equipment on the panel, elements 78 and 79 beingindicator lamps for indicating that the power and steam are on whenilluminated. Operation of the cut-off gates 15 is indicated throughindicator lamps 80-84, inclusive, and the fact that the sequence ofoperations for sequential control is on, is indicated by a lamp 85.

Start, stop and reset control switches for the system, of thepush-button type, are indicated respectively on the panel board in thesame row with the indicator lamp 85, at 86, 87 and 88, respectively.

Operation of the rotary feeder gates for each boiler is indicated byindicator lamps 90 and 91, indicator lamps 90 being for boiler 9 andindicator lamps 91 being for boiier 10, as shown.

Operations of the rear pass conduit by opening of gate 3 under certainconditions of operation, as hereinafter described, is indicated by anindicator lamp 92. On either side of the indicator lamp 92 are selectorswitches 95 and 96, arranged for selective manual operation of gates 1or 2, or 4 or 5, as indicated.

L kewise, manual operation switches for the rotary feeder gates ofboiler 9 are indicated at 98, while similar switches for the manual oeration of the rotary gates of boiler 10 are indicated at 99, one foreach gate.

The system is adjusted for manual or automatic operation in connectionwith one or both boilers by means of a rotary se ector switch 100, whichis provided with a control lever 101 by which the various contacts (notshown) are adjusted for vario s conditions of operation. In the presentexample, six different conditions of operation are provided for, thesebeing off, automatic operation of boiler 9, automatic operation ofboiler 10, automatic operation of boilers 9 and 10, sequentially manualoperation of boilers 9 and 10, and operation of the rear pass and bottomash portions of the system, also manually.

The control panel contains, in addition to the control and indicatingelements hereinbefore referred to, two motor driven multiplex ormultiple circuit timers lTR and 2TR. These control the major operationsof the ash handling system in connection with boilers 9 and 10,respectively, when under automatic operation.

The condition of the ash discharge system at each boiler outletisrecorded automatically during the operation by a multiple stylusrecorder 102, also located on the panel. In the present example, this isprovided with a plurality of recording styli corresponding in number tothe number of automatically operated rotary feeder gates, being eight innumber. It will be appreciated, however, that in the present example,the operation of two boiler units with four rotary gates each is only byway of example, as a greater or lesser number of rotary gates and asingle boiler may be controlled in accordance with the invention, forthe sequential and automatic handling of the ash disposal.

The vacuum switch 56 is mounted on the lower portion of the panel,between two relay panels 103 and 104 which are located on the rear ofthe panel and contain the various control and timer relays which areincorporated in the system, the group 103 being directed more to thecontrol of the boiler 9, both automatically and manually, while thegroup 104 contains relays for the control of the boiler 10. These relaysand their contacts in operation will further be understood from aconsideration of Figures 3A and 3B, taken together along with thepreceding figures.

Referring now to Figures 3A and 3B, jointly, as a single schematiccircuit diagram of a system embodying the invention, in which the samereference characters are used for like parts as in the preceding andsubsequent figures, the entire control system is energized and operatesin response to current supplied through two supply leads S and 106. Lead105 has three main branch leads 107, 108 and 109 for energizing thevarious pieces of apparatus and control circuits in the system, whereasthe supply lead 106 is connected mainly to the various pairs of switchcontacts of the selector switch 100, through a branch conductor 110connected with one of each pair of switch contacts as indicated, inaddition to certain of the control circuits and elements directly, aswill hereinafter be described.

The pairs of selector switch contacts are designated by the letters A,B, C, D, E, F, G, H, J, K, L, M, N, P, Q, R, S, W and X. For conveniencein considering the operation of the system, the pairs of contacts whichare closed in response to each adjustment of the selector switch aregrouped within the dotted outline of the switch 100, as shown, the groupB, E, F, J and X being closed when the selector switch is set forautomatic operation of boiler 9; the group C, H, and M being closed forauto matic operation of boiler 10; the group D, G, N, K being closed forautomatic operation of boilers 9 and 10; the group L, P, Q, R, W beingclosed for manual operation of boilers 9 and 10; and the group A, Sbeing closed for manual operation of the rear pass and bottom ashportion of the system.

It will thus be seen that, as the selector switches are adjusted to anyone of the five operating positions indicated in Figures 2 and 3A,certain selected ones of the control circuits are energized from thepower supply leads 106110, and the operation of the system is such thatthe circuit is then completed through various control elements andcircuits to the opposite power supply lead 105, through one of thebranch leads 107, 108 or 109.

The operating current provided by the power supply leads 105-106 may bederived from any suitable alternating current source in the systemshown. In the present example, the supply leads are connected through astep-down transformer 112 to higher voltage alternating current powersupply mains 113, which may be assumed to supply current at 440 voltsalternating current. Suitable fuses 114 are provided in each supply leadconnection with the transformer on the low voltage side. It will also benoted that the indicator lamp 78 is connected directly across the leads105106 to indicate when the power is on.

While the rotary feeder gate motors may, in some installations, beoperated also directly from the power supply leads 105-406, in thepresent example, for a large power plant installation, the rotary feedergate motors require a considerable amount of power and, accordingly, areshown as being of the three-phase type supplied from three-phasealternating current power supply circuits and 116. The motors areconnected with the three-phase power supply circuits through the motorcontroller units 35, as shown more particularly in Figure 3B, and apreferred form of the controller unit is shown by the interior circuitarrangement of one unit for the motor 25. Each of the other motorcontrollers is the same and connected in the same manner.

As will be seen, alternating current power is taken from the three-phasesupply circuit, through the contacts 118 of a three-phase switch, to themotor, the motor connection including overload relay coils 119, whichoperate on overload to release a reset switch 120. The reset switch isin circuit with the operating coil 121 for the controller which, whenenergized, closes the contacts 118. One terminal of the coil 121 isconnected to supply branch 107 and the opposite side is connectedthrough the reset switch and a selector switch 122 with a controlcircuit lead 123 or a control circuit lead 124. The switch has threepositions as indicated, and is shown in the position in which itprovides connection with the control circuit lead 124 for automaticoperation of the system, whereas when it is moved to provide aconnection with the control circuit lead 123, it is arranged to causethe motor to operate under manual control. A third, or intermediate,position is provided for turning off the motor.

In a similar manner, the motor controller units for the motors 26, 27and 28 are each connected with the control circuit lead 123 in parallelrelation to each other, and individually to the remaining controlcircuit leads 125, 126 and 127 of the group of four control leads, ofwhich lead 124 is the first, the connections with the latter leads beingrespectively through leads 128, 129 and 130 for the motors concernedwith the operation of the boiler 9.

For the motors 30, 31, 32 and 33 for the rotary feeder gates of boiler10, the motor controller units are connected in parallel to the controlcircuit lead 123, and individually to a second group of four controlleads 132, 133, 134 and 135, the latter connections being made, asshown, through their respective circuit connections leads 136, 137, 138and 139.

With this arrangement, the various motor controllers may be set to theoff position, whereby the operating windings of the control switches maybe disconnected from circuit to maintain the motor in a shut-downcondition when repairing or otherwise working on the individual rotarygates, and may selectively be connected for automatic or manualoperation, the manual operation connection being that provided throughthe common control circuit lead 123. For automatic operation theindividual control units are connected with the individual controlcircuit leads 124127 for boiler 9, and 132135 for boiler 10. Thus, whenso connected, energizing each of the individual leads provides a circuitthrough the motor controller switch operating coil back to lead 107 andthe power supply lead 105. Energy is supplied from the lead 106 to theleads 124127 and leads 132-435 sequentially and in timed relationthrough the operation of the contacts T2T5 of the motor driven timingrelay 1TR and the contacts T2-T5 of the motor driven timing relay 2TR,to which the leads referred to are shown as directly connected. it willthus be seen that automatic operation of the rotary gates is controlledby the timing relays 1TR and 2TR. Tracing of the circuits from thecontacts referred to will hereinafter be given.

It will be noted that, in addition to the operating coils of the motorcontrollers, there is connected with each of the selective controlcircuit leads 124-127 and 132- 135 a stylus operating coil of themultiple stylus recorder 102, so that the multiple stylus recorder mayoperate in response to operation of each rotary feeder gate. In thepresent example, the stylus operating coils 138 are individuallyconnected each with one of the leads referred to, and in common with alead 139, which in turn is connected through a lead 140 with the branchsupply lead 107 in common with the operating coils of the motorcontrollers 35, whereby when the individual motor controllers areenergized selectively to operate each of the rotary feeder gates inturn, the corresponding individual stylus of the multiple stylusrecorder is operated simultaneously.

It will be noted that the multiple stylus recorder is of the motordriven type, having a motor operating winding 142, which is likewiseconnected with the supply lead 140, above referred to, and is providedwith a control lead 143 which is connected to the various contacts ofrelays hereinbefore referred to, and to one of the pair of contacts W ofthe switch 100. Thus, when the switch is closed for manual operation,the timing motor stylus is energized, and is likewise energized undercertain other operating conditions, as will hereinafter appear. Therecorder is provided with a pilot light 145, which is connected directlyacross or in parallel with the motor winding 142 and is, therefore,energized when the motor opcrates, that is, when the recorder is inoperation, and serves to indicate to an attendant that the recorder isoperating at the proper times.

It will also be noted that the rotary feeder gate indicator lamps 90 and91 are connected in parallel with supply branch 107 through a supplylead 145, and individually to the rotary feeder gate motor and recordercontrol leads 124127 and 132435, so that there is in parallel with eachmotor and recorder stylus, one of the rotary feeder gate indicator pilotlamps. These lamps, therefore, indicate to an attendant at the controlpanel the individual rotary feeder gate motor which is operating wheneach lamp is energized. The manual-automatic switches 98 and 99,associated with each rotary feeder gate indicator on the control panel,and illustrated in the circuit diagram of Figure 3B, are of thetwo-point type, shown in the open position, and operative when closed toprovide a circuit connection from the control circuit lead 123 to thecontrol circuit lead to which the associated lamp indicator isconnected.

In this manner, for manual operation the individual switches 98 and 99may be closed to energize any one of the leads 124-127 and 132135 fromthe control lead 123, so that the individual feeder gate motor andrecording stylus corresponding thereto may be operated without automaticcontrol. tion, may be seen by tracing the supply lead 123 through acommon connection lead 146 and the contacts 147 of a control relay 8CR,thence through a connection lead 148 to the contacts Q of the selectorswitch 100.

It will thus be seen that when the selector switch is set for manualcontrol of the boilers 9 and 10, and the contacts Q are used, operatingcurrent will be supplied from the supply lead 106 through the lead 148,the contacts 147, the lead 146 to each of the motor controllers 35, andto the switches 98 and 99, and if any of these switches is closed,operating current will then flow from the lead 146 through therespective recorder stylus operating coil to the lead 139, the lead 140and the lead 107, back to the supply lead 105. Likewise, if any one ofthe motor controllers 35 is set for manual or Run operation, thecorresponding operating coil will be energized in a similar manner, fromthe lead 123, and the return circuit will be provided directly with thelead 107 as hereinbefore described. This phase of the operation willhereinafter be considered more fully.

In addition to the control relay 8CR, there are eight other similarcontrol relays, 1CR7CR and 9CR. All of these relays have a plurality ofcontacts which are operated simultaneously when the relay is energized,and while they may be of any suitable type, for clearer illustration andunderstanding of the invention they are shown herein as being of thesolenoid coil operating type, and the contacts are arranged in pairs tobe closed by the movement of the individually insulated shorting barsbetween pairs of contacts. The connection with the solenoid operatingcore is indicated in dotted lines. Thus. in the case of the first relay8CR, above referred to, an additional pair of contacts 150 are providedfor simultaneous closure by operation of a solenoid core 151 when therelay operating coil 152 is energized.

The remainder of the control relays are similarly arranged foroperation, being provided with operating coils 153-160 for relays1CR-7CR and 9CR, respectively. It will be noted that one terminal 161 ofeach control relay coil is connected with the operating current supplybranch lead 109, so that all of the relay coils are connected inparallel with one supply lead 105. The opposite terminals 162 areconnected through the various control circuits and switch connections tothe branch 110, and thence to the opposite operating current supply lead106, as will hereinafter appear.

The control relay 1CR is provided with five pairs of contacts 165-169,inclusive, all of which are normally open, but are simultaneously closedwhen the relay is energized. The relay ZCR has only three pairs ofcontacts This connection for manual opera- 170472, inclusive, whichlikewise are normally open but are simultaneously closed when the relayis energized. This same arrangement is also true of control relay 3CR,except that this relay has only two pairs of contacts 173 and 174.

The control relay 4CR is provided with three normally open pairs ofcontacts 175, 176 and 177, and one pair of normally closed contacts 178.When energized, the relay contacts 177 are closed, while the contacts178 are opened. This same arrangement is provided for relay SCR, whichhas three normally open pairs of contacts 179, 180 and 181, and one pairof normally closed contacts 182. The control relay 6CR is provided withtwo normally open pairs of contacts 183 and 184. It may be noted inpassing that this control relay is concerned only with the rear pass andbottom ash disposal under manual operation, and is in no way concernedwith the automatic operation of the system, as will be seen from thefact that the operating connection for the terminal 162 of the relaycoil 158 is connected through a lead 185 only with the pair of contactsA of the selector switch 100, and, therefore, the relay winding 158 andthe rear pass indicator lamp 92 (which is connected in parallel with therelay winding 158 through the contacts 183) are energized only when thecontacts A are closed for rear pass and bottom ash manual operation.

The control relay 7CR, like the control relays 4CR and SCR, is providedwith three normally open pairs of contacts 186, 187 and 188, and alsoone pair of normally closed contacts 189. When the relay is energized,the contacts 186188 are closed and the contacts 189 are opened. Thecontrol relay 8CR is provided with only two pairs of contacts 147 and150, both of which are normally open, as hereinbefore described, whilethe control relay 9CR is provided with three normally open pairs ofcontacts 190, 191 and 192, all of which are closed when the relay isenergized.

It will be noted that the control relays 1CR9CR are arranged in a group,one above the other, in the circuit diagram of Figure 3A, for a moreready understanding of the operation of the system, in that all of therelays of this group are instantaneous'opening and instantaneous closingrelays, having no time control feature, and function substantiallywholly as relays or electrically operable multiple contact switches ofthe two-point or two position type. Accordingly, any suitable relays forthe purpose may be provided in lieu of those shown.

In a similar manner, the timing relays for the system, which are sevenin number, have been arranged as a group, one above the other, andinclude the two motor operated timing relays 1TR and 2TR, hereinbeforereferred to, these being on the panel front and being etfectively motordriven timers.

Referring to Figure 4, along with Figures 3A and 3B, the timing orcontact closure sequence of the timing relays or motor driven timers lTRand 2TR is shown for a further understanding of their operation. In theparticular system in which the relays are provided, the contacts T1 ofboth relays close for five seconds only, during a timing cycle of 300seconds. After a pause of ten seconds, the contacts T2, T3, T4 and T5 ofboth timing relays lTR and 2TR Close consecutively for 60 seconds, witha ten-second interval between, and this is followed by a ten-secondinterval, after which the contacts T6 close and remain closed forfifteen seconds. During this time the contacts T1 are closed for theinterval of five seconds, as hereinbefore mentioned.

The motor driven timers lTR and 2TR are provided with operating motors195 and 196, respectively, having motor operating windings 197 and 198.One terminal 199 of each motor operating winding is connected with thebranch supply circuit lead 108, which in turn is connected with thesupply lead 105. The opposite terminals 200 and 201, respectively, ofthe timing motors 195 and 196 are connected with respective controlleads 202 and 203, the former being connected with one of the pair ofcontacts 192 of the control relay 9CR, while the latter is connectedwith one of the pair of contacts 172 of the control relay 2CR. isprovided with a reset coil 205. These are each connected with the commonsupply lead 108, and in parallel with a control lead 206 through whichthey are simultaneously energized in connection with the contacts 175 ofthe control relay 4CR. The tracing of this circuit may be completedthrough a lead 207 and thence through a In addition, each motor driventimer bus connection 208 with the contacts B, C and D of the selectorswitch 100.

Thus it will be seen that the reset coils 205 of the motor driven timersllTR and 2TR are simultaneously energized whenever the selector switchis set for automatic operation for boiler 9, boiler 10, or both boilers,and the control relay 4CR is energized to close the contacts 175. Itwill likewise be seen that the operating winding 156 of the relay 4CR isconnected through a control lead 210 with the reset control switch 88,and thence to the supply bus 208 which, as hereinbefore pointed out, isenergized from the lead 110 whenever the selector switch is adjusted forautomatic operation in any one of the three positions. Therefore, whenthe reset button or switch is operated, the control relay 4CR isenergized, and under such conditions the reset coils 205 of the timingrelays lTR and 2TR are energized to reset the timers to zero, forstarting the timing sequence shown in Figure 4. The fact that the relaycontacts may be reset is schematically illustrated in the diagram by thedotted clutch connections 211 interposed between the reset coils 205 andthe contacts of the relays 1TR and 2TR.

The remainder of the timing relays are arranged for timed closing ortimed opening with operation otherwise instantaneous. For example, thetiming relay 3TR is instantaneous opening and time closing, requiring afifteensecond interval to close. The relays 4TR and STR areinstantaneous closing and time opening, requiring a threesecond intervalto open. The timing relay 6TR is instantaneous opening and time closing,requiring a ten-second interval to close, and the timing relay 7TR isinstantaneous closing and time opening, requiring a SO-second intervalto open.

While any suitable multiple contact timing release may be provided foruse in the system with the timing arrangement above indicated, forpurpose of illustration, the same solenoid coil operating type has beenshown in the drawing as for the control relays, comprising a solenoidoperating coil and pairs of contacts arranged to be opened or closed byshorting bars operated in unison and insulated one from the other. Inthe present example, the relay 3TR is provided with an operating coil orwinding 212, and operates to close a pair of contacts 213 whenenergized. The relay is provided with additional contacts 214, which arenot used. This is likewise true of the timing relay STR, the operatingwinding 215 of which, when energized, serves to close a pair of contacts216, other pairs of contacts 217 not being used.

The relay 4TR is provided with an operating winding 220, which operateswhen energized to close two pairs of contacts 221 and 222simultaneously. The timing relays 6TR and 7TR are each provided with apair of normally closed contacts 225 and 226, which are opened when therelay coils or windings 227 and 228 are energized. Since these relaysare of a commercial type, additiongl unused contacts 229 are providedtherein as indicate It will be noted that each of the relays is shownwith a rectangular element 230, connected at the opposite end of thecontact operating system from the solenoid operating coil, and this maybe taken to represent a dash pot or other timing means by which-thedesired timing operation is attained. As such relays are commerciallyavailable and well known, no further description is believed to benecessary.

The main operating relay of the system is control relay 1CR, theoperating winding 153 of which is connected in parallel with thesequence On, indicating lamp 85, and is further connected through acontrol lead 232 with the contacts 178 of control relay 4CR, thencethrough a control lead 233 with the stop switch 87 and start switch 86.The stop switch 87 is connected through relay contacts 166 of thecontrol relay 1CR in parallel with the start switch 86, with a lead 234,and thence to the bus connection 208 for the selector switch contactsfor automatic operation in any one of the three positions hereinbeforereferred to. Therefore, upon setting the selector switch to any one ofthe automatic operation positions, operation of the start switch 86energizes the operating winding 153 of the relay lCR, which then remainsenergized through the contacts 166 and the stop switch 87. All of thecontacts remain closed until the stop button or switch 87 is operated toopen the circuit.

The operating coil 154 of the relay 2CR and the Steam On indicating lamp79, in parallel therewith through the contacts 170, is energized througha control lead 236, thence through the switch contact 65 of the steampressure gauge 63, returning through a return lead 237 to the mainsupply bus 110 as shown. Therefore, as soon as the steam is applied forthe steam jet for producing a vacuum on the conduit system, with apressure suflicient to close the switch 65, the relay 20K is energized,together with the indicating lamp 79, and the contacts of the relay 2CRremain closed as long as the steam is on. Since the system cannotoperate without the application of steam to the jet, this operates as asafety or control relay for preventing operation of the system in theabsence of steam pressure on the et.

The operating winding of the relay 3CR is energized through a controllead 240, which is connected through the normally open contacts 213 ofthe timing relay 3TR, thence through a bus connection 241 and a lead 242with the contacts 169 of the control relay lCR, and is, there.

fore, energized upon closure of the contacts 213 of the timing relay 3TRwhen control relay lCR is energized.

The circuit connections for the control relay operating windings, asabove described for the control relays 1CR, 2CR and 3CR, may further beseen and more readily understood by reference to the simplifiedschematic circuit diagram of the system shown in Figure 5, to which,along with Figures 3A and 3B, attention is now directed, and in which,as hereinbefore pointed out, like reference characters throughout referto like parts, circuits and circuit elements. It is obvious that, in thesimplified circuit diagram of Figure 5, only the fundamental circuitconnections are shown, and one each of the rotary gate motors forboilers 9 and 10, and one each of the recording styli for the recorderin connection with each boiler are shown, as illustrating theconnections for the other rotary gate motors and recording styli whichare shown completely in the circuit diagram of Figures 3A and 38.However, the selector switch is shown in the same position and with thecontacts arranged in the same sequence in Figure 5 as in Figure 3A, forready reference to the five selective positions of operation for theswitch.

From a consideration of Figures 3A, 3B and 5, it will be seen that theoperating winding 156 for the control relay 4CR is not only energizedthrough the lead 210 and the reset button or switch 88 from the busconnection 208 and any one of the selector switch contacts B, C or D,but is also energized through other circuit connections provided byvarious relays, as more clearly shown in Figure 5 in connection withselector switch contacts E, M and N.

The contacts 176 and 177 of the control relay 4CR are hold-in contactswhich serve to hold the operating winding 156 energized whenever therelay is first initially energized, for example, by closing of the resetswitch 88. For boiler 9, it will be seen that when the relay contacts176 are closed, the operating winding 156 of relay 4CR receives energyfor operation through the contacts 221 of the timing relay 4TR and theselector switch contacts E. This circuit may be traced in Figure 3A fromthe contacts 176 through a connection lead 245 to one of the terminalsT1 of timing relay lTR, and thence through a lead 246 to the contacts221 of timing relay 4TR. From the contacts 221 the circuit is completedthrough a lead 247 connected to the contacts of the selector switch, andthence to the power supply bus 110. The relay, therefore, remainsenergized after the initial energization through the circuit connectionprovided by way of holding or hold-in contacts 176 and the contacts 221of the timing relay 4TR. It will be noted that the contacts T1 of thetiming relay lTR are connected in parallel with the hold-in contacts 176of the control relay 4CR, whereby the relay 4CR may momentarily beoperated to close when the timing relay ITR reaches a position forclosing the contacts T1.

Referring to the diagram of Figure 4, it will be seen that thesecontacts T1 are closed in the system of the present example,substantially momentarily for a period of five seconds, and at a timewhen the contacts T6 are likewise closed, the latter contacts beingclosed for five seconds preceding and following the closing of thecontacts T1. The remaining contact of the contacts T1 of timing relaylTR is connected through a lead 248 to the lead 210 and the terminal 162of the operating winding 156 of the control relay 4CR.

A similar circuit connection for energizing the operating winding 156 ofthe control relay 4CR is provided when the selector switch 100 is set toclose in the automatic operating position for boiler and in the positionfor automatic operation of boilers 9 and 10. In either of the latterpositions, the contacts M or N are closed and this serves to complete anoperating circuit connection with the contacts 216 of the timing relaySTR. This connection, in Figure 3A, may be traced through a busconnection 250 and a lead 251. From the contacts 216 of the timing relaySTR the circuit further may be traced through a lead 252 to the contactsT1 of the timing relay 2TR and through a lead 253 continuing therefromto the contacts 177 of the control relay 4CR. From this point theconnection ties in with the contacts 176, the operating winding 156 andthe reset button or switch 88 and the circuitry hereinbefore described.It will be noted that the contacts T1 of the timing relay 2TR areeffectively connected in parallel with the contacts 177 by reason of theconnection lead 253 and an extension of the lead 248 to provide aconnection 254 with the remaining contact of the contacts T1 of thetiming relay 2TR.

Therefore, it will be seen that, for operation of boiler 9, the controlrelay 4CR is energized through the timing relay 4TR contacts 221,whereas for boiler 10 the relay is energized through the timing relaySTR contacts 216 and that, in addition to the hold-in contacts 1.76 and177, the relay may likewise be energized through the contacts T1 oftiming relay 1TR, for the operation of boiler 9, and through thecontacts T1 of timing relay 2TR for operation of boiler 10 or boilers 9and 10.

The control relay SCR is likewise an important control element of thesystem and is energized only when the control relay ICR is energizedthrough three circuit connections provided by the relays 4TR, SCR andthe selector switch contacts F, H and G. The connection with thecontacts H of the selector switch is direct from the control relaycontacts 167 of the control relay ICR, the circuit being traced from theterminal 162 of the relay operating coil 167 through a lead 256 to thecontacts 167 and thence through a connection lead 257 with a lead 258,which is connected with the contacts H of the selector switch 100.

Branch connection leads 259 and 260 from the lead 258 provideconnections, respectively, with the contacts 222 of the timing relay 4TRand the contacts 180 of the control relay SCR. The remaining terminalsof the contacts 222 and 180 are connected in parallel through a lead 261and a lead 262.

The control relay 6CR is concerned only with the operation of the rearpass and bottom ash removal under manual operating conditions, which hashereinbefore been described in connection with the circuitry of Figure3A. Accordingly, the circuit for the control relay 6CR, with theselector switch contacts A, does not appear in the simplified circuitdiagram of Figure 5, although the control contacts 184 appear therein,as will be understood hereinafter in connection with the description ofoperation.

The relays 7CR and 8CR are arranged to be operated simultaneously, andfor that purpose the operating windings 152 and 159 are connected inparallel through a connection lead 265 with a control lead 266-267,Which in turn is connected with the contacts 226 of timing relay 7TR andthe contacts 225 of the timing relay 6TR, as lvgell as the contacts 187of the control relay 7CR itse From the contacts 225 and 226, parallelcircuit connections may be traced to the contacts 165 and 184 of controlrelays 1CR and 6CR, respectively, in parallel, and to the contacts P ofthe selector switch 100. In the circuit of Figure 5, this is easilytraceable and it will be noted that, in the connection from the contacts226 of the timing relay 7TR, the contacts 186 of the control relay 7CRare interposed in series. In the circuit of Figure 3A, these connectionsmay be traced from the contacts 225 of the timing relay 6TR through alead 269 to the contacts 186, with a branch lead connection 270 with thecontacts 184 and a continuing branch connection 271 with the contacts Pof the selector switch. The connection further may be traced through alead 272 from the lead 269 and the contacts 225 to the contacts 165 ofthe control relay ICR. From the contacts 165 and 184, connections aremade through leads 273 and 274, respectively, with the main supply lead110 of the system.

The lead 266-267 is likewise tied in with the contacts 226 of the timingrelays 7TR. From the contacts 226, a circuit connection through a lead275 and the contacts 186 is provided with the circuit lead 269, withwhich the contacts of the control relay 1CR and the contacts 184 of thecontrol relay 6CR are connected. With this arrangement, it will be seenthat the control relays 7CR and 8CR are energized when either of thetiming relays 6TR or 7TR is energized simultaneously with theenergization of either of the control relays ICR or 6CR or when theselector switch is set for manual operation and the contacts P areclosed. The control through the timing relay 7TR is further made subjectto the operation of the control relay 7CR and closure of the contacts186.

This control network for the relays 7CR and 8CR further controls thetiming relay 6TR through the contacts 187 of the control relay 7CR, aswill be seen from an inspection of the circuitry of Figure 5. In otherwords, the operating winding 227 of the timing relay 6TR is connected inparallel with the operating windings 152 and 159, respectively, of thecontrol relays 8CR and 7CR through the contacts 187 of the control relay7CR. This circuit is shown in detail in Figure 3A and may be traced fromthe windings 159 and 152 through the lead 266, thence through thecontacts 187 and a connection lead 280 to the operating winding 227, andthrough the winding 227 to the supply lead 108 The operating winding 228of the timing relay 7TR is likewise connected into the presentlyconsidered control network associated with the control relays 7CR and8CR, being connected with the network between the contacts 186 ofcontrol relay 7CR and the contacts 226 of the timing relay 7TR toreceive operating current through either the contacts 165 of controlrelay ICR or the contacts 184 of control relay 60R whenever the contacts186 of control relay 7CR are closed. Likewise, the same operation occurswhen the contacts P of the selector switch are closed and the relaycontacts 186 are closed at the same time. This circuit may be traced inFigure 3A from the operating winding 228 of the timing relay 7TR to thesupply lead 108 and an extension circuit connection from the lead 275and the contacts 226.

The operating winding 160 of the control relay 9CR is connected througha terminal 161 with the power supply lead 109, while the terminal 162 isconnected through a lead 284 with the normally closed contacts 182 ofthe control relay SCR and through a further extension lead 285 with thecontacts X of the selector switch 100, being in the group which areclosed when the normally open switch is set for automatic operation ofboiler 9. A return lead 286 from the contacts X, which are the onlycontacts not connected with the supply bus 110, is connected also withthe opposite one of the normally closed contacts 182 of the controlrelay 5CR, so that the contacts 182 and the contac s X are in parallel.

A further connection from the lead 286 is provided through a circuitlead 287 with a bus connection 288 which is connected with one of thecontacts T6 of the timing relay lTR contacts of the control relay 9CRand the contacts 168 of the control relay lCR. The contacts 168 are inturn connected through a lead 290 with a bus connection 291 and thecontacts I and K of the selector switch in parallel. The control relay9CR is operated, therefore, when the operating winding 160 is energizedthrough closure of the contacts X, or of the contacts 182 of the controlrelay SCR, which are in parallel, together with closure of the contacts168 of the control relay ICR and either of the contacts I or K of theselector switch 100.

These same contacts I and K of the selector switch 100 and the contacts168 of the control relay lCR serve simultaneously to control theenergization of the operating Window 220 of timing relay 4TR or theoperating solenoid 4-0 and the indicator lamp 30 of the cut-off gate 1.The latter connection is provided through the contacts 190 of thecontrol relay 9CR, while the former connection is made through thecontacts T6 of the timing relay lTR, as is clear from the simplifieddiagram of Figure 5. In Figures 3A and 3B, these connections areprovided in the case of the operating winding 220 for the timing relay4TR on one side or" the winding 220, directly with the supply lead 108,whereas the opposite Winding is connected through a lead 295' with thecontacts T6 of the timing 13 relay 1TR, and thence through the contactsto the lead 288.

The connection for the operating solenoid 40 of cut-off gate 1 isprovided directly with the supply lead 107 on one side, and through asupply lead 296 with the contacts 190 of the control relay 9CR, andthence through the contacts 190 to the lead 283. It will thus be seenthat the cut-off gate 1 is under the control of contact 168 of relay 1CRand is operated whenever the contacts 190 of the relays 9CR are closed.Likewise, the timing relay 4TR is operated under the control of thecontacts 168 of the control relay ICR, and momentarily whenever thecontacts T6 of the timing relay 1TR are closed. As appears in thediagram of Figure 4, the contacts T6 are closed over a period of fifteenseconds, being open during the remainder of the timing cycle of therelay lTR.

Cut-off gate 2 is operated by the solenoid 41, and is provided with theindicator lamp 81 in parallel therewith. This is controlled by thecontacts 179 of the control relay SCR, together with the contacts M or Nof the selector switch 100. The operating circuit may be traced inFigures 3A and 38 from the contacts M and N in parallel, as provided bythe circuit lead 250, thence through the contacts 179 of the controlrelay SCR to a circuit connection lead 298, which in turn is connectedwith the operating solenoid 41 and the indicator lamp 81. The circuit iscompleted through connection of the operating solenoid 41 and theindicator lamp 81 with the supply branch lead 107. As pointed outhereinbefore, this is connected with the power supply lead 105.

It will be noted that the manual operation switch 95 for gates 1 and 2is provided with a contact 300, connected with the supply lead 298 forthe cut-off gate 2 operating solenoid 4i and a contact 301, connectedwith the supply lead 296 for the cut-off gate 1 operating solenoid 40. Aselector contact 302, shown in the normally open position, is arrangedto connect with either of the contacts 300 or 301 selectively, to closethe switch in one direction or the other for manual operation of thecut-off gates 1 and 2. For this purpose, the selector contact 302 isconnected through supply lead 304 with the contacts L of the selectorswitch, which are closed for manual operation of the boilers 9 and 10.

In this manner, when the selector switch is closed for manual operationof boilers 9 and 10, the cut-off gates 1 and 2 may be operated by manualoperation of the selector switch 95. In a similar manner, the whollymanual cutoff gates 4 and 5 (Figure 3B) are controlled by the manualcontrol switch 96. This switch, like the selector switch 95, is providedwith a contact 305, connected through a control lead 306 with theoperating solenoid 43 and the indicator lamp 83 for the cut-off gate 4,while a second contact 308 is connected through the control lead 309with the operating solenoid 44 and indicator lamp 84 for the cut-offgate 5.

Return connection to the power supply is provided byconnection for thesolenoids 43 and 44 and the indicator lamps 83 and 84 with the branchsupply lead 107. The operating contact 310 for the selector switch 95may be moved from a normally open position, as shown, into connectionwith either of the contacts 305 or 308 to manually operate the cut-offgates 4 and 5, respectively, the power supply connection from thecontact 310 being indicated by the circuit lead 311 with the contacts Rof the selector switch 100, this being in the group for manual operationof boilers 9 and 10 as shown in Figures 3A and 3B. These connections areomitted in Figure 5, as

the manual operating connections are clear in the circuit of Figures 3Aand 3B.

While cut-oif gates 4 and 5 are manually operable by selector switch 96when the contacts are closed, the cut-off gate 3 is wholly operated bythe selector switch 100 through closure of the contacts S for the rearpass and bottom ash manual position of the selector switch. For thispurpose, the contacts S provide a supply connection from the supply leador bus 110 and a connection lead 312 to the operating solenoid 42 andindicator lamp 82 for the cut-off gate 3. The circuit is completedthrough connection of the indicator lamp and operating solenoid with thebranch supply lead 107, as shown in Figure 3B. The circuit connectionsfor the cut-off gate 3, like those for the cut-off gates 4 and 5, areomitted in Figure 5 for the purpose of simplifying the drawing and forthe reason that the connections are clear in the main diagram of Figures3A and 3B.

The motor driven timing relays ITR and 2TR are operated through controlrelays 2CR and 3CR, both of these relays being energized whenever thetiming motors are operated. In addition, the timing motor for the relay1TR is under control of the relay 9CR, while the timing motor for thetiming relay 2TR is under control of the relay 5CR. The timing motor forthe relay ITR is, furthermore, under control of the contacts F or G ofthe selector switch, whereas the timing motor for the relay ZTR is undercontrol of the contacts M or N of the selector switch. These connectionsare clear from the schematic circuit of Figure 5, and may be traced inthe complete circuit diagram of the system shown in Figures 3A and 3B.

From the terminal 200 of the timing relay motor operating winding 197for the timing relay lTR, a circuit may be traced through the lead 202and the contacts 192 of the control relay 9CR, and thence through aconnection lead 315 to the contacts 173 of the control relay 3CR, andthence through a connection lead 316 and the contacts 171 of the controlrelay 2CR to the bus connection 261 for the contacts F and G of theselector switch, and thence to the supply lead or bus 110.

Tracing, now, the corresponding circuit for the timing relay 2TR, theterminal 201 of the motor operating winding 198 is connected through alead 203 with the contacts 172 of the control relay ZCR, and thencethrough a connection lead 318 to the contacts 174 of the control relay3CR. The circuit is completed from the contacts 174 through a connectionlead 319 to the contacts 179 of the control relay 50R, and thence to thebus connection 250 and the contacts M and N of the selector switch.

From a study of the circuit diagram, particularly as shown in Figure 5,it will be seen that the timing motor for the relay 2TR and the cut-oifgate 2 are controlled through the contacts 179 of the control relay SCR.In a similar manner, the cut-off gate 1 and the timing motor for therelay lTR are both controlled by the relay 9CR through the operation ofcontacts 190 and 192. This is for the reason that, as appears in Figurel, the cut-off gate 1 is provided for boiler 9 and cut-off gate 2 isprovided for boiler 10. Likewise, timing relay 1TR serves to operate therotary feeder gates for boiler 9, whereas timing relay 2TR serves tooperate the rotary feeder gates for boiler 10. Therefore, the respectivecut-01f gates must be operated with the rotary feeder gates for therespective boilers. Further description of the operation of the rotaryfeeder gate motors and of the recorder will be given hereinafter.

The electrical operating element or solenoid 52 for the steam valve isconnected with thebranch supply lead 107 at one terminal and atthe'other terminal is connected through a control lead 325 with thecontacts 188, the control relay 7CR and, through the contacts 188, witha supply lead 326 which is connected with the branch supply bus or leadfor the opposite side of the power supply circuit. The steam valve isoperated, that is, opened, whenever the solenoid 52 is energized byclosure of the contacts 188 of the control relay 7CR.

The timing relay 7CR is controlled in unison with the timing motor ofthe timing relay 2TR and with the cutoff gate 2 through operation of thecontacts 179 of control relay 5CR. For this purpose, the operatingwinding 215 of the timing relay 5TR is connected at one terminal withthe branch supply lead 108. The opposite terminal is connected through acontrol lead 327 with the contacts T6 of timing relay 2TR, and from thecontacts T6 the connection is continued to the lead 298, which in turnis connected with the operating solenoid 41 for cut-off gate 2, as shownmore clearly in Figure 5, and at the same time is connected at a pointbetween the contacts 179 of control relay 50R and the contacts 174 ofcontrol relay 3CR. This connection is shown in Figure 3A by theconnection for the lead 298 from the contacts T6 of the timing relay 2TRto the contacts 179 of control relay 50R, and thence to the contacts 174of control relay 3CR. The operating winding 215 of timing relay STR is,therefore, operated whenever the contacts T6 of the timing relay 2TRclose for the 15-second interval, as indicated in Figure 4, and thecontacts 179 of control reay SCR are closed. This is assuming that theselector switch is set for automatic operation of either boiler 10 orboilers 9 and 10, in which case the contacts M or N of the selectorswitch are closed.

The remaining relay operating winding is that of the timing relay 3TR,and its operating connection will now be described. The operatingwinding 21-2 is connected on one side with the branch power supply lead108, while the other terminal of the coil is connected to the contact 57of the vacuum switch 56 through an extended circuit connection lead 330.The return connection from the vacuum switch 56 is provided inconnection with the contact 58"and is provided by a return conductor 331which is connected with the lead 241 in the circuitry previouslydescribed and leads, as shown in the circuit diagram of Figure 5, backthrough the contacts 169 of control relay 10K to the power supply branch110. Therefore, the timing relay 3TR is energized whenever the vacuumswitch contacts 57 and 58 are closed and the control relay lCR isenergized.

The timing relay 3TR may also be energized whenever the control relay1CR is energized, and the contacts 169 are closed, at the same time thecontrol relay 7CR is deenergized so that its normally closed contacts189 are the closed position as shown in Figures 3A and 5. These contactsprovide a shunt connection across the contacts of the vacuum switch 56,as is more clearly seen in Figure 5 and as may be traced in the circuitdiagram of Figure 3A from one terminal of the control relay operatingwinding 212 through a control lead 333 to the contacts 189 of thecontrol relay 7CR, and thence to the lead 241 hereinbefore mentioned,thereby placing the contacts 189 in parallel with the contacts 57 and 58of the vacuum switch 56.

Referring again to the motor driven timing relays lTR and 2TR, thecircuit connections and control effect of the timing contacts T1 and T6of these relays have hereinbefore been described and the circuitscontrolled thereby have been traced. The remaining contacts T2-T5,inclusive, for each of these timing relays are utilized for the remotecontrol of the corresponding number of rotary feeder gate motors, timingrelay lTR serving to control the motors for boiler 9 and timing relay2TR serving to control the motors for boiler 10.

One of each pair of the contacts referred to for both timing relays isconnected in parallel through a circuit connection 335, shown in Figure3A, and the branch connection 336 therefrom to the contacts 150 of thecontrol relay SCR. The operating circuit may then be traced from thecontacts 150 through a connection lead 337 with one of the contacts 189,control relay 7CR, and thence to the circuit connection lead 241hereinbefore referred to. This connection is easily traceable in Figure5 from the lead 335 to the contacts 150, and thence to the contacts 169of control relay lCR and one side of the power supply circuit 106 or110, the latter being the branch provided for connection with theselector switch.

The timing contacts T2 to T5, inclusive, of the timing relay lTR areconnected to provide, selectively, circuit connections between the lead335 and each of the leads 124-127, respectively, which are connected, asshown in Figure 33, each with one of the stylus operating Windings 138of the multiple stylus recorder 102 and with motor control units 135 forthe feeder gate motors 25, 26, 27 and 28, respectively.

As described previously, application of operating voltage to the leads124-127 serves to operate the respective recorder sty i and therespective motors through the motor control units. For example, assumingthe contacts T2 of the timing relay lTR to be closed, current flows fromthe lead 335 throu h the contacts and the lead 124 to the first orleft-hand (in the drawing) stylus operating winding 138 of the multiplestylus recorder, and thence throu h the lead 139, the supply lead 107and the connection therewith to the main supply lead 105, therebyenergizing the sty us operating winding.

Simultaneously. current flows from the lead 124 through selector switch122 of the motor control unit for the rotary feeder gate motor 25,thence throu h the reset contacts 124) and the operating switch winding121 back to the branch supply lead 187 and the main supply lead 195, asabove described. thereby energizing the Winding 121, causing thethree-phase contactor switch 118 to close and to sup ly the m tor 25with energy from the power supply leads 115. The motor then operates todrive the rotary feeder gate 11 for boiler 9.

In a similar manner, the remaining motors 26, 27 and 28 and thecorresponding stylus operating winding 138 for the multiple stylusrecorder 102 are energized successively as the contacts T3, T 4 and T5close to energize the power supply leads 125, 126 and 127. Referring toFigure 4, it will be seen in what order the contacts T2-T5 will closeand for what duration of time in the present example. As set up for theparticular operation here provided, the contacts remain closed for aperiod of 60 seconds and remain open throughout the remainder of thetiming cycle, with a lO-second interval between the closing of thecontacts T2-T3, the contacts T3T4, and the contacts T t-T5, as appearsmore clearly in the diagram of Figure 5. n

It will be noted that the rotary feeder gate indicators for boiler 9 areconnected each with one of the leads 124-127, to be energizedsimultaneously with energization of the corresponding feeder gate motorand recorder stylus, the indicator lamps being connected through areturn circuit lead at 45 with the branch supply lead 107, in commonwith the feeder gate motors and recorder.

It will also be seen that when the manual-auto switches 98 are movedfrom the normally open position shown to the closed position, connectionis made by each switch between its respective control leads 124-127 andthe control lead 146, which in turn is connected through the contacts147 and a lead 148 with the contacts Q of the selector switch, andthence to the supply circuit lead 106-110. Therefore, when the selectorswitch is set for manual operation of boilers 9 and 10, thereby closingcontacts Q, any one of the feeder gate motors and the correspondingstylus of the recorder may be operated by closing any of the manual-autoswitches 98 for the boiler 9. As will hereinafter be seen, this providesfor the manual operation and clearing of the feeder gates directly fromthe panel board shown in Figure 2, or other suitable control point atwhich the switches 98 may be located. As shown in Figure 2, and also asrepresented in Figure 3B, the rotary feeder gate indicators and themanual auto switches are located in close association on the panelboard.

The operation of the multiple stylus recorder and the rotary feeder gatemotors 30, 31, 32 and 33 for boller 10 is carried out in a similarmanner by the successive closure of the contacts T2-T5 of the timingrelay ZTR, whereby the control leads 133-135 (Figure 3B) are energizedin the same manner as the corresponding control leads 124-127 for boiler9. In this manner the motors 30-33 may be operated in succession withthe rotary feeder gate indicators 91 and the recording stylicorresponding thereto. The manual-auto switches 98 serve to energize thecontrol leads 132-135 selectively for the individual manual operation ofthe rotary feeder gate motors for boiler 10, whenever the lead 146 isenergized by the closure of the contacts Q of the selector switch asabove described.

In the simplified circuit diagram of Figure 5, a single circuitconnection is shown for the contacts T2 of the timing relays lTR and 2TRin connection with the corresponding recorder stylus operating windings138 and the rotary gate motors 25 and 30, for example. In this circuitdiagram also, the manual control switches for the motor control unitsare indicated to show the full operation of the system and the rotarygate motors are indicated as being operated directly by energizationfrom the supply leads -406, as would be the case where sufficient powermight be supplied thereby. It should be understood, of course, that themotor designations M in the schematic diagram of Figure 5 may be eitherthe motor or the operating solenoid for the contactor switch as abovedescribed.

Automatic operation of the system may now be con sidered, withparticular reference to Figure 5. For automatic operation of boiler 9alone, the selector switch 100 is turned to the boiler 9 position,thereby closing contacts B, E, F, I and X only, and the reset button 88is pressed if necessary. The pilot or indicator lamps for power andsteam are lighted, when power is on and the steam is at a pressuresutficient to close the switch 65. The start button 86 is then pressed,and this brings in the relay 1CR, which maintains the closed position,that is, is energized, through the relay 4CR normally closed contacts178 from the contact B of selector switch 100 and the contacts 166through stop switch 87.

The relay 1CR contacts energize the coils of relays 7CR and SCR, throughtiming relay 6TR normally closed contacts 225. Relay 7CR picks up relays6TR and 7TR, opening 6TR normally closed contacts, holding in relays 7CRand 8CR through timing relay 7TR normally closed contacts 226. At theend of 50 seconds, the timing relay 7TR contacts 226 (normally closed)open, deenergizing relays 7CR and 8CR and timing relay 6TR and 7TRcoils. Timing relay 6TR normally closed contacts 225 remain open for 10seconds after the relay 6TR coil is deenergized, then reclose, allowingrepetition of the SO seconds-10 seconds action above. Thus the relays7CR and 8CR will close for 50 seconds and open for 10 seconds, as longas this group circuit for boiler 9 is energized. The relay 7CR contacts187 energize four-Way solenoid 52 for the steam valve, which producesvacuum for the system.

The relay 1CR contacts 168 from auto 9 (J) selector contact, energizethe relay 9CR. Through auto 9 (X) contacts, the relay 9CR remainsenergized and contacts 190 are then closed to energize the solenoid 40of the cut-01f gate 1 and associated pilot or indicator lamp 80.

The relay 9CR contacts 191 energize the recorder motor 142 and indicatorlamp 145. Also the relay 1CR contacts 169 will energize the pneumatictimer relay 3TR if the gate 1 ash pipe is clear, so that no vacuum isapplied on vacuum switch 56 for a period of 15 seconds, and the contactsclose. The relay STR normally open contacts 213 close, therebyenergizing the relay 3CR.

The relay 3CR contacts 173 complete the operating circuit to the 1TRtimer motor 195 from lead 110 through auto 9 (F) contacts, thencethrough relay 9CR (normally open) contacts 192 and contacts 171 of relayZCR (normally open), thence through contacts 173 and the timing motorwinding 197 to the supply lead 108. The timing relay lTR motor beginstiming in accordance with contact schedule as shown in Figure 4, andcontacts 1TR-T2 close, moving recorder pen 1 and starting rotary gate11. This lights the pilot for the rotary gate 11. Rotary gate 11 remainsin operation for 35 seconds, then is deenergized by release of timingrelay 7TR. In ten seconds, rotary gate 11 restores, then operates 50seconds on and 10 seconds off until ash is completely drawn out of gate11. At this time, the vacuum switch 56 will remain closed for 15 secondsor more, allowing the timing relay 3TR to bring in the control relay3CR. This allows the timing relay 1TR motor to advance, thereby openingcontacts 1TR-T2 and closing contacts 1TRT3. This transfers operation andrecording from rotary gate 11 to rotary gate 12, on which the aboveoperation repeats. However, the initial on time of rotary gate 12 willbe different from that of rotary gate 11, since the clearing of rotarygate 11 of ash may occur at any time during the 50 second-l secondcycling of timing relays 6TR-7TR.

Operation of rotary gates 12, 13 and 14 occurs in sequence with transferbeing effected by the timing relay contacts 1TR--T3, T4 and T as eachhopper is cleared of ash. Timing of the relay lTR advances only as thecontrol relay 3CR is energized (due to lack of vacuum in the ash pipefor more than 15 seconds). Running time of each rotary gate is recorded,in 50 seconds on, seconds off intervals, on respective pens of therecorder 102. Completion of the cycle and resetting of auto 9 controltakes place after rotary gate 14 has been cleared. The timing relay 3TR,after a -second interval, energizes control relay SCR which allowstiming relay lTR to close T6 contacts, whereupon the timing relay 4TR isenergized. The relay 4TR normally open contacts 222 energize the controlrelay SCR, which operates but has no function in auto 9 position.

Five seconds after the contacts 1TR-6 close, the contacts 1TRT1 close,allowing timing relay 4TR normally open contacts 221 to pick up 4CR,which then maintain a circuit around 1TRT1. The relay 4 CR operates,energizing reset clutches 205 of both tim ng relays lTR and 2TR and therelay lTR resets, opening all contacts. The timing relay 5TR coil 215 isdeenergized. The relay 4CR releases control the relay lCR by opening 4CRnormally closed contacts 178. The relay lCR releases relays SCR and 9CR.The pilot 145 is extinguished and the motor 142 recorder is turned off.The relay 4CR remains in operation for a total of three seconds, until4TR-normally open contacts 221 have timed out, releasing the relay 4CRand the timing relay lTR and 2TR clutch coils. At this point theoperating cycle is completed and the system is at rest.

Considering now operation of the auto-boiler 10 alone, the selectorswitch 100 is set to boiler 19 position, thereby closing contacts C, Hand M only, and the start button or switch 86 is operated. The relay lCRpicks up and remains energized through selector switch contacts (C). Therelay lCR energizes the relay SCR, and the relay SCR (normally closed)contacts 182 prevent relay 9CR from operating. Also the relay SCR,normally open contacts 179 energize the operating solenoid 41 of cut offgate 2 and the associated pilot indicator 81. The relay SCR normallyopen contacts 181 energize the recorder motor 142 and indicator lamp145.

The relay lCR normally open contacts energize the relay 6TR-7CR-8CRcircuit which initiates a cycle of 50 seconds on and 10 seconds off forthe vacuum supply on the conduit system. The relay lCR energizes thetiming relay 3TR through the normally closed contacts 57-58 of thevacuum switch 56. If ash pipe from the boiler 10 to the cut-oil? gate 2is clear, preventing vacuum from being established, the timing relay 3TR(after 15 seconds) will operate the relay 3CR. The latter relay closesthe operating circuit to the timing relay 2TR motor timer 196 whichadvances the timing according to the graph shown in Figure 4. Thecontacts 2TRT2, T3, T4 and T5 close in turn, in the same manner as thecorresponding contacts of lTR controlling boiler 9, effecting thedrawing of ash from rotary gates, 15, 16, 17 and 18 in turn, until ashis exhausted from the four hoppers of boiler 10.

The completion of the cycle and reset operation of boiler 10 is asfollows: After the ash is exhausted from rotary gate 18, the vacuum canno longer be established, and in fifteen seconds the timing relay 3TRoperates the relay 3CR. The contacts ZTR-Tfi, energizing the timingrelay 5TR which operates fully. The timing relay 5TR normally opencontacts 216 close, making ready the operating circuit to the relay 4CRthrough contacts 2TRT1. Five seconds after the contacts 2TR-T6 close,the 2TR-T1 contacts close, operating the relay 4CR, and maintaining acircuit around contacts 2TRT1, through STR contacts 176. This holds therelay 4CR in operation for three seconds until the relay 5TR times out.

The relay 4CR, in operating, releases the relay ICR, whichin turnreleases the relays 5CR and SCR. The relay 3CR stops the timing relay2TR timer motor 196- 198. At this time, the relay 4CR energizes thereset clutches 205 of both times ITR and 2TR, holding these in operationfor three seconds while the timing relay 5TR times out. The reset actionof the timing relay ZTR opens the circuit through contacts 2TR--T6,which deenergizes the relay 5T R coil 215. The timing relay STR, inopening its contacts 216, releases relay 4CR, which releases the resetclutches 205 of both timers lTR and 2TR. The system is completelyrestored at this point of operation.

For operation of both boilers 9 and 10 automatically, the selectorswitch 100 is turned to boiler 9 and 10 position, thereby closingcontacts D, G, N and K, and the start button or switch 86 is operated asbefore. The relay 1CR picks up and provides a circuit connection toselector switch contact (D). The sequence of operation includesoperation of control relays, pneumatic timers and motor driven timer lTRthe same as in boiler 9 operation, until the rotary gate 14 has beencleared. Then the operation transfers from boiler 9 to boiler 10.

The timing relays 4TR and 1TRT1 contacts cannot energize relay 4CR,since selector switch contact (E) is open. The relay SCR is operated bythe timing relay 4TR, and releases the relay 9CR, stopping the timingrelay lTR motor but not resetting it. lTR-TG and T1 remain closed (seeFigure 4). The relay R, in releasing, deenergizes the cut-oh" gate 1,and the relay SCR, in operating, energizes the cut-01f gate 2, allowingair to be drawn into the ash pipe serving boiler It). When air has beendrawn for 15 seconds, the timing relay 3TR operates the relay SCR,energizing the timer motor of timing relay 2TR. The timing relay 2TR inturn closes its contacts T2, T3, T4 and T5 by which rotary gates 15, 16,17 and 18 are cleared of ash.

After all gates are cleared, the contacts 2TR-T6 close, energizing thetiming relay STR, which prepares the circuit for operating relay 4CRthrough selector switch contact N. Reset operation of both motor timerclutches 205 proceeds when timing relay 2T R contact (T1) closes fiveseconds later, as in boiler 10 operation. The system is then completelyrestored to normal and rest condition.

In the present system, all control operations and signals are at 110volts, 60 cycles, obtained through 30A fuses 114 in each side of thecontrol line. The capacity of the control transformer may be of theorder of 1.5 kva. continuously. The large fuses are used to permitfrequent operation of cut-elf gate solenoids momentary heavy currentwhich draw at 110 volts.

Opening of any one of the five solenoid-operated cutoff gates isindicated by an associated pilot or indicator lamp. Rotation of any ofthe eight motor driven rotary gates is also indicated by an associatedpilot lamp, when the gate is operated from the controller. The variousindicator lamps may have various colors for ready identification.

Travel of the chart of the operation recorder 102 is indicated by thechart lamp being on inside the recorder. Fully reset condition of themotor driven timers 1TR and ZTR is indicated by the respective resetclutch solenoids being energized for three seconds continuously. Thisallows the timing means to be restored to their normal positions. In apreferred type of timer, known commercially as the Eagle multiplex motordriven synchronous timer, the timing means will restore only on thefirst reset position of clutch solenoids, being held thereafter in thenormal position until operated by the timer motors.

It will be seen that the timing relays 6TR and 7T R control the periodicapplication of the vacuum to the conduit system and the operation of therotary feeder gates through control relays 7CR and 8CR, respectively.The timing relay 6TR is arranged for instant opening and time closing(10 seconds), while the timing relay 7TR is an ranged for instantclosing and time opening (50 seconds). Therefore, the system operatesfor 50 second intervals to remove ash and pauses for 10 seconds, andrepeats until the ash is fully removed from each rotary gate position.The vacuum falls and the closing of the vacuum switch contacts for 15seconds allows lS-second time closing of relay 3TR, which in turnoperates relay 3CR and causes the particular motor operated timing relayITR or ZTR to advance to the next contact for energizing the next rotarygate motor in the sequence.

For manual operation, referring generally to the circuit of Figure 5,the selector switch 101) is set to the manual 9 and 10 position, whichcloses contacts L, P, Q, R and W. The switch 95 is operated to openeither of the gates 1 or 2, being moved right or left from the off orcenter position as viewed in Figure 2.

The two-position switches 98 or 99 are then operated to put any one ofthe rotary feeder gates in motion, being moved from auto to manualposition. The recorder motor is then energized through contacts (W) andthe relay circuit 6TR--7TR7CR8CR is in operation through the circuitsconnected with contact P. When SCR closes contacts 147, in the sequence,the rotary gate motor selected will operate through current from contactQ of the selector switch and the associated recorder stylus will recordthe operation in 50 and 10 second on and off intervals until theselectors 98 or 99 are turned back to auto operation. Complete clearanceof the ash from each point in the system is indicated by the falling ofthe vacuum at the gauge to or toward zero. The stack may be clearedlikewise by opening gates 4 and 5 by operation of switch 96, while theselector switch 100 is in the manual position, since the vacuumcontrolling relays 6TR and 7TR are in operation to pulse the steam valveon for 50 seconds while relay 7TR is opening (T. O. 50 sec.) and off forthe lO-second interval that relay 6TR is closing.

Manual operation may be obtained in the same manner while operatingautomatically to assist in clearing any sluggish ash condition at anyrotary gate. To return to automatic operation, the operation selectorswitch 100 is turned back to the previous position at which automaticoperation was progressing and the start switch is operated. Operationthen continues from the point at which it was interrupted.

However, it will be seen that if the reset switch is operated, thetiming relays 1TR and 2TR will be reset and cause the automatic cycle tostart with the first rotary gate feeder again.

For rear pass and bottom ash clearance, the operation selector switch100 is moved to the rear pass position shown in Figure 2, which causescontacts A and S only to be closed, and the operation may be seenreadily from an inspection of Figures 3A and 3B. This energizes cut- 20off gate 2 and relay 6CR is energized. This causes relays 6TR, 7TR, 7CRand 8CR to be energized. The steam jet is turned on, thereby puttingvacuum on the system in the 50-second and l0-second cycle withoutoperating the recorder. The falling of the vacuum on the gauge indicatesclearance of the ash.

From the foregoing description of a present preferred system, it will beseen that, in accordance with the invention, an improved ash handlingsystem includes means for periodically applying vacuum to a conduitsystem and operating a plurality of ash feeding units in sequence undercontrol of timing relays which advance the cycle of operation inaccordance with the ash condition at each point. This provides forhandling the ash from a plurality of ash producing units by electricalcontrol from a centralized unit having instruments for recording theduration of each operational step as a measure of the ash discharge fromeach point.

The system provides sequential control of the various rotary feedermeans in dependence upon the vacuum condition in the conveyor conduitand operates to advance the timing of the operation in steps which areinitiated as soon as each unit is cleared.

Sequential control of a plurality of feeders for each ash producing unitis provided, in accordance with the invention, by a minimum of timingand control relays in a simplified electrical system having a singleselector switch and a relatively small number of controls, making foreasy operation and minimum attendance.

It will be understood, of course, that the present invention issusceptible of various changes and modifications which may be made fromtime to time without departing from the general principles or realspirit of the invention and it is accordingly intended to claim the samebroadly, as well as specifically, as indicated in the appended claims.

What is claimed as new and useful is:

1. An improved ash handling system for power plants and the like havinga plurality of ash producing units, comprising a closed ash conveyingconduit connected with said ash producing units, a plurality of electricmotor operated rotary gate ash feeder means connected with said conduitat each of said ash producing units for feeding ash thereto from each ofsaid units in sequence, means for maintaining a vacuum on said conduit,and vacuum operated switch means responsive to the vacuum in saidconduit for effecting sequential operation of said feeder means.

2. An improved ash handling system as defined in claim 1, wherein theelectric motor operated feeder means are further sequentially controlledby electrical timing relay means providing a predetermined time ofoperation for each of the feeder means.

3. An improved ash handling system as defined in claim 1, wherein theelectric motor operated feeder means are further sequentially controlledby electrical timing relay means providing a predetermined time ofoperation for each of the feeder means, and wherein said timing relaymeans is controlled by additional relay means responsive to operation ofthe vacuum operated switch means, whereby reduction of vacuum in saidconduit in response to reduction of the ash content operates to advancethe operation of the system.

4. An improved ash handling system for power plants and the like havinga plurality of ash producing units, comprising a closed ash conveyingconduit connected with said ash producing units, a plurality of electricmotor operated rotary gate ash feeder means connected with said conduitat each of said ash producing units for feeding ash thereto from each ofsaid units in sequence, means for maintaining a vacuum on said conduit,vacuum operated switch means responsive to the vacuum in said conduitfor effecting sequential operation of said feeder means, and means forrecording the time duration of the operation of each ash feeder means asa measure of the ash content derived from each unit.

5. An improved ash handling system for fuel burning power plants and thelike comprising in combination, closed ash conveying conduit meanshaving a branched conduit connection for each ash producing unit of theplant, a plurality of rotary ash feeder gates connected with eachconduit branch in connection with each ash producing unit for feedingash to the conduit means, individual electric motor means for operatingsaid feeder gates, relay controlled electric circuit means for operat-21 ing said rotary feeder gates in predetermined sequence, means forapplying a vacuum to said conduit system for withdrawing ash therefrom,and vacuum switch means connected with said conduit for controlling thesequence of operation of said rotary feeder gates.

6. An improved ash handling system as defined in claim 5, wherein amultiple stylus recorder is provided for indicating the duration ofoperation of each rotary feeder gate and is provided with individualelectrically operated styli connected for operation each with one ofsaid rotary feeder gate motors, whereby the operation 'of eachfeedergate may be compared with that of the others for duration ofoperation as an indication of the condition of operation of the ashdisposal system.

7. An improved ash handling system as defined in claim 5, wherein therotary feeder gates are sequentially responsive through electricallyoperated timing relays one for each ash producing unit, and wherein thetiming relays are selectively controlled by said vacuum switch means.

8. An improved ash handling system as defined in claim 6, whereinelectrical control relays are selectively operable for automatic andmanual operation of the system through a single selector switchproviding select able sequential operating connections therefor.

9. An ash handling system adapted for sequential control of a pluralityof ash producing units comprising in combination, ash conveying conduitmeans having a branch for each ash producing unit, means for creating avacuum on said conduit means for ash withdrawal, a vacuum controlledswitch connected with said conduit means for controlling said system inresponse to the vacuum condition therein, a plurality of electric motoroperated rotary feeder gates for feeding ash from each unit to saidconduit means at a plurality of dilferent ash collecting locations, anelectrical control system connected between said vacuum switch and saidrotary feeder gates including electric motor drive means for said gatesand electrical control and timing relay means therefor, a selectorswitch and electrical circuits in said control system for selectiveindividual and joint control of said units, and indicating and recordingelements connected with said system for effecting continuous ashwithdrawal sequentially from said units in predetermined order.

10. In an ash disposal system for power plants and the like, thecombination with a plurality of ash producing units, of conduit meansfor withdrawing ash therefrom, and including vacuum producing meansadapted for periodic operation, a vacuum operated switch connected withsaid conduit means and operable in response to change in vacuum,electric motor driven rotary gate means for feeding ash to said conduitmeans from a plurality of points in connection with each of said ashproducing units, electric relay controlled means for actuating saidrotary gate means sequentially in response to changes in vacuum in saidconduit means, selector switch means for adjusting said system formanual and automatic operation sequentially from unit to unit andsequentially through each unit to effect ash removal from point to pointthroughout the system, and means for indicating the time duration of ashremoval from each point in each unit and including a multiple stylusrecorder having recording styli connected for response to operation ofeach ash feeder means.

11. A system for continuously removing ash from a plurality of ash'producing units comprising in combination, an ash conveying conduithaving a branch conduit for each unit, a plurality of electric motordriven rotary gate ash feeding devices for each unit connected with a.branch of said conduit, gate means for selectively placing each conduitbranch in operation, said gate means being electrically operable, anelectric motor for each of said ash feeding devices, means for applyinga vacuum to said conduit to eifect ash withdrawal thereto, the degree ofvacuum being determined by the ash delivered by said devices, vacuumswitching means responsive to the vacuum condition in said conduit, amotor driven timing relay for each of said units providing sequentialcontrol of the motors for each unit, and an electrical control systemconnected with said vacuum switching means and including control relaysfor operating said timing relays in response to changes in the vacuumcondition in said conduit, whereby said motors are sequentially operatedin predetermined order cyclically to withdraw ash from said units, andcontrol means for initiating each cycle of operation.

12. A system as defined in claim 11, wherein means are provided forindicating the duration of operation of each feeder device to provide anindication of the quantity of ash removed through each device during acycle of operation of the system.

13. A system as defined in claim 11, wherein means are provided forindicating the duration of operation of each feeder device to provide anindication of the quantity of ash removed through each device during acycle of operation of the system, and wherein a single multiplecontactselector switch is provided having a plurality of operating positionsproviding selectively for operation of each unit individually andcollectively and for manual operation of the system.

14. A system as defined in claim 13, wherein a plurality of timingrelays are provided for introducing in the cycle of operation of thesystem a predetermined operating time and a predetermined pause betweenash withdrawal operations.

15. A system as defined in claim 14, wherein one of the control relaysprovides for starting and stopping the operation of said system, andwherein individual start and stop switches are provided for operatingsaid relay.

16. A system for continuously removing ash from a plurality of ashproducing units comprising in combination, an ash conveying conduithaving a branch for each of said units, a plurality of rotary gate ashfeeding devices for each unit individually connected with a branch ofsaid conduit, individual electric motor drive means for each of said ashfeeding devices, means for applying vacuum to said conduit to effect ashwithdrawal through a selected branch, the degree of vacuum beingdetermined by the ash delivered by said devices, vacuum switch meansoperably responsive to the vacuum condition in said conduit, electricmotor driven timing relay means providing sequential operation of theelectric motor drive means for each unit, selector switch means forselectively connecting the timing relay means for each of said units foroperation of said ash feeding devices in predetermined sequence, acontrol relay connected with each of said timing relay means forapplying current therethrough for operating the electric motor drivemeans for said ash feeding devices under sequential control of saidtiming relays, a pair of timing relays for controlling the operation ofsaid last-named control relay and said electric motor drive means, oneof said pair of timing relays being adjusted to operate over apredetermined period of time and the other of said pair of timing relaysbeing adjusted to operate over a shorter time inter val for initiatingsuccessive cycles of operation for each of said electric motor drivemeans, and a relay responsive to operation of said vacuum switch meansfor applying operating current to said motor driven timing relay meansdependent upon a low vacuum condition in said conduit to advance thesequential operation of the electric motor drive means and the ashfeeding devices.

17. A system for continuously removing ash from a plurality of ashproducing units, comprising in combination, an ash conveying conduithaving a branch for each of said units, a plurality of rotary ashfeeding devices for each unit connected with a branch of said conduit,individual electric motor drive means for each of said ash feedingdevices, means for applying a vacuum to said conduit to effect ashwithdrawal therethrough, vacuum switch means connected with said conduitand operably responsive to a low vacuum condition therein, electricmotor driven timing relay means providing sequential operation of themotor drive means for each unit, a control relay connected with andoperable by said vacuum switch means to apply operating current to saidmotor driven timing relay means selectively to advance the operatingcycle to the next successive motor driven ash feeding device in thesequence, control relays for simultaneously energizing the vacuumapplying means for the conduit and the selected electric motor drivemeans for the ash feeding devices through said motor driven timing relaymeans, and a pair of timing relays connected with and controlling saidlast-named relays simultaneously and including a timing relay whichoperates with a predetermined long time delay and a second timing relaywhich operates with a relatively short time delay to effect periodicoperation of each sequentially selected motor driven ash feeding deviceand periodic stopping of said device under control of said vacuum switchmeans, whereby the ash feeding devices are sequentially operated inpredetermined order cyclically to withdraw ash from said units.

18. An improved ash handling system for power plants and the like havinga plurality of ash producing units, comprising a closed ash conveyingconduit connected with said ash producing units, a plurality of electricmotor operated rotary ash feeder gates connected with said conduit ateach of said ash producing units, electric motor driven timing means forsequentially selecting each of said ash feeder gates for operation,control relay means including two interconnected time delay relays foroperating each selected ash feeder gate over a predetermined longer timeinterval and for stopping the operation thereof over a shorter timeinterval in successive cycles, relaycontrolled steam jet meanssimultaneously operable with said last-named means for applying a vacuumto said conduit to effect ash withdrawal therethrough during saidpredetermined longer time interval, vacuum switch means connected withsaid conduit and responsive to a low vacuum condition therein foroperation of said firstnamed electric motor driven timing means, saidcontrol relay means being adapted for periodically energizing eachselected motor operated rotary feeder gate and said steam jet means tocreate a vacuum in said system over said predetermined longer timeinterval and for stopping said gate and cutting off said steam jet meansover said relatively shorter time interval, whereby the ash withdrawalat each selected gate is alternately stopped and started, and relaycontrolled means responsive to the operation of the vacuum switch foradvancing the operation of said motor driven timing relays to energize asucceeding gate in the sequence, said relays operating to advancetheoperational sequence when the vacuum is sub stantially Zero.

19. An ash handling system for a plurality of ash producing unitscomprising in combination, conduit means connected with said ashproducing units for conveying ash therefrom, means for applyingperiodically a vacuum to said conduit means, a plurality of electricmotor operated rotary ash feeder means for each unit connected with saidconduit means, and electrical control means for actuating said feedermeans in sequence and responsive to the vacuum in said conduit means,said electrical control means including a motor driven timing relay foreach unit for energizing the ash feeder means therefor individually andsequentially in predetermined order, motor driven timing relays foreffecting an advance in the sequence of operations from one feeder meansto the next in predetermined order, a control switch responsive to thevacuum in said conduit means for controlling said last-named relays inresponse to a reduction in the vacuum to substantially zero, andadditional timing relays for operating each of said ash feeder means fora predetermined time interval and for stopping the operation thereofover a shorter time interval periodically.

20. A system as defined in claim 19, in which a multiple unit recorderis provided in connection with each ash feeder means for recording thetime of operation as an indication of a condition of operation of saidfeeder means. 7

21. A system as defined in claim 20, in which all operations arecontrolled from a central control unit and wherein a selector switch isprovided for presetting all operations of the system.

22. An improved ash handling system for a multiple unit fuel burningpower plant comprising in combination, means including a plurality ofelectric motor driven rotary feeder gates and a common conduit connectedtherewith for selectively withdrawing ash from each unit at a pluralityof different points, an electronic control circuit network including aplurality of timing and control relay means, and selector means for thecircuits of said network effective to connect said relay means foreffecting ash withdrawal under predetermined vacuum condition in saidconduit sequentially from each withdrawal point of a unit, said timingand control relay means including a main control relay responsive tostart and stop operations for the system, a vacuum control relay forsaid conduit, an ash feeder control relay, a pair of timing relays forcontrolling said last-named relays simultaneously periodically for apredetermined time interval with delay intervals therebetween insuccessive cycles, two motor driven sequential timing relays for eachunit for effecting operation of the feeder gates and withdrawal of ashsequentially from each point in predetermined order, an automatic resetrelay for said last-named timing relays, and a relay responsive to thevacuum in said conduit for effecting operation of said sequential timingrelays in response to a reduction of the vacuum in the conduit, wherebysaid units are cleared of ash in predetermined order sequentially inresponse to changes in the vacuum in said conduit.

References Cited in the file of this patent UNITED STATES PATENTS2,213,886 Potter Sept. 3, 1940 2,276,134 Windham Mar. 10, 1942 2,420,217Allen May 6, 1947 2,477,414 McBride July 26, 1949 2,514,333 Mylting July4, 1950

